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@PHDTHESIS{Slowik:276404,
      author       = {Slowik, Jan Malte},
      title        = {{Q}uantum effects in nonresonant x-ray scattering},
      issn         = {1435-8085},
      school       = {Universität Hamburg},
      type         = {Dr.},
      address      = {Hamburg},
      publisher    = {Verlag Deutsches Elektronen-Synchrotron},
      reportid     = {PUBDB-2015-04615, DESY-THESIS-2015-045},
      series       = {DESY-THESIS},
      pages        = {176},
      year         = {2015},
      note         = {Universität Hamburg, Diss., 2015},
      abstract     = {Due to their versatile properties, x rays are a unique tool
                      to investigate the structure and dynamics of matter. X-ray
                      scattering is the fundamental principle of many imaging
                      techniques. Examples are x-ray crystallography, which
                      recently celebrated one hundred years and is currently the
                      leading method in structure determination of proteins, as
                      well as X-ray phase contrast imaging (PCI), which is an
                      imaging technique with countless applications in biology,
                      medicine, etc. The technological development of X-ray free
                      electron lasers (XFEL) has brought x-ray imaging at the edge
                      of a new scientific revolution. XFELs offer ultrashort x-ray
                      pulses with unprecedented high x-ray fluence and excellent
                      spatial coherence properties. These properties make them an
                      outstanding radiation source for x-ray scattering
                      experiments, providing ultrafast temporal resolution as well
                      as atomic spatial resolution. However, the radiation-matter
                      interaction in XFEL experiments also advances into a novel
                      regime. This demands a sound theoretical fundament to
                      describe and explore the new experimental possibilities.
                      This dissertation is dedicated to the theoretical study of
                      non resonant x-ray scattering. As the first topic, I
                      consider the near-field imaging by propagation based x-ray
                      phase contrast imaging (PCI). I devise a novel theory of
                      PCI, in which radiation and matter are quantized.
                      Remarkably, the crucial interference term automatically
                      excludes contributions from inelastic scattering. This
                      explains the success of the classical description thus far.
                      The second topic of the thesis is the x-ray imaging of
                      coherent electronic motion, where quantum effects become
                      particularly apparent. The electron density of coherent
                      electronic wave packets –important in charge transfer and
                      bond breaking – varies in time, typically on femto- or
                      attosecond time scales. In the near future, XFELs are
                      envisaged to provide attosecond x-ray pulses, opening the
                      possibility for time-resolved ultrafast x-ray scattering
                      experiments. In the quantum theory it has however been
                      revealed that x-ray scattering patterns of electronic motion
                      are related to complex spatio-temporal correlations, instead
                      of the instantaneous electron density. I scrutinize the
                      time-resolved scattering pattern from coherent electronic
                      wave packets. I show that time-resolved PCI recovers the
                      instantaneous electron density of electronic motion. For the
                      far-field diffraction scattering pattern, I analyze the
                      influence of photon energy resolution of the detector.
                      Moreover, I demonstrate that x-ray scattering from a crystal
                      of identical wave packets also recovers the instantaneous
                      electron density. I point out that a generalized electron
                      density propagator of he wave packet can be reconstructed
                      from a scattering experiment. Finally, I propose
                      time-resolved Compton scattering of electronic wave packets.
                      I show that x-ray scattering with large energy transfer can
                      be used to recover the instantaneous momentum space density
                      of the target. The third topic of this dissertation is
                      Compton scattering in single molecule coherent diffractive
                      imaging (CDI). The structure determination of single
                      macromolecules via CDI is one of the key applications of
                      XFELs. The structure of the molecule can be reconstructed
                      from the elastic diffraction pattern. Inelastic x-ray
                      scattering generates a background signal, which I determine
                      for typical high-intensity imaging conditions. I find that
                      at high x-ray fluence the background signal becomes
                      dominating, posing a problem for high resolution imaging.
                      The strong ionization by the x-ray pulse may ionize several
                      electrons per atom. Scattering from these free electrons
                      makes amaj or contribution to the background signal. I
                      present and discuss detailed numerical studies for different
                      x-ray fluence and photon energy.},
      cin          = {FS-CFEL-3},
      cid          = {I:(DE-H253)FS-CFEL-3-20120731},
      pnm          = {6211 - Extreme States of Matter: From Cold Ions to Hot
                      Plasmas (POF3-621)},
      pid          = {G:(DE-HGF)POF3-6211},
      experiment   = {EXP:(DE-MLZ)NOSPEC-20140101},
      typ          = {PUB:(DE-HGF)29 / PUB:(DE-HGF)11},
      doi          = {10.3204/DESY-THESIS-2015-045},
      url          = {https://bib-pubdb1.desy.de/record/276404},
}